text: /*
   *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree. An additional intellectual property rights grant can be found
   *  in the file PATENTS.  All contributing project authors may
   *  be found in the AUTHORS file in the root of the source tree.
   */
  
  /******************************************************************
  
   iLBC Speech Coder ANSI-C Source Code
  
   WebRtcIlbcfix_CbMemEnergyCalc.c
  
  ******************************************************************/
  
  #include "modules/audio_coding/codecs/ilbc/defines.h"
  
  /* Compute the energy of the rest of the cb memory
   * by step wise adding and subtracting the next
   * sample and the last sample respectively */
  void WebRtcIlbcfix_CbMemEnergyCalc(
      int32_t energy,   /* (i) input start energy */
      size_t range,   /* (i) number of iterations */
      int16_t *ppi,   /* (i) input pointer 1 */
      int16_t *ppo,   /* (i) input pointer 2 */
      int16_t *energyW16,  /* (o) Energy in the CB vectors */
      int16_t *energyShifts, /* (o) Shift value of the energy */
      int scale,   /* (i) The scaling of all energy values */
      size_t base_size  /* (i) Index to where energy values should be stored */
                                     )
  {
    size_t j;
    int16_t shft;
    int32_t tmp;
    int16_t *eSh_ptr;
    int16_t *eW16_ptr;
  
  
    eSh_ptr  = &energyShifts[1+base_size];
    eW16_ptr = &energyW16[1+base_size];
  
    for (j = 0; j + 1 < range; j++) {
  
      /* Calculate next energy by a +/-
         operation on the edge samples */
      tmp = (*ppi) * (*ppi) - (*ppo) * (*ppo);
      energy += tmp >> scale;
      energy = WEBRTC_SPL_MAX(energy, 0);
  
      ppi--;
      ppo--;
  
      /* Normalize the energy into a int16_t and store
         the number of shifts */
  
      shft = (int16_t)WebRtcSpl_NormW32(energy);
      *eSh_ptr++ = shft;
  
      tmp = energy << shft;
      *eW16_ptr++ = (int16_t)(tmp >> 16);
    }
  }
  